1. Field of the Invention
The present invention relates generally to the fields of medicine and microbiology. More particularly, it concerns methods of reducing microbial organisms from surfaces, including indwelling medical devices, medical equipment and other surfaces, for example.
2. Description of Related Art
With the widespread of infectious diseases at the global level, the use of highly effective and safe disinfectants has been the number one public health challenge around the globe. Most of the infectious diseases that are associated with high morbidity and mortality are transmitted through skin contact or contact with a colonized surface in the environment. This includes highly resistant bacterial organisms, which is becoming a widely spread community organism, such as, for example, methicillin-resistant Staphylococcus aureus (MRSA) or other resistant bacteria, fungi, viruses (such as the H1N1 and SARS, for example) as well as other parasitic pathogens. Unfortunately, the currently widely used disinfectants in various settings, including hospitals, daycare centers, and other places that host high-risk individuals, are marred by several disadvantages, particularly being hazardous in terms of their toxicity, instability and the potential health risks to the users. None of the currently widely used chemical disinfectants is ideal in terms of its safety, lack of toxicity and broad-spectrum activity against various pathogens.
Chlorine Bleach Solutions
Household and institutional chlorine bleaches contain 5.25% active sodium hypochlorite when they are manufactured. The remaining 94.75% is primarily water. Chlorinated compounds such as sodium hypochlorite when diluted in water form hypochlorous acid. This acid is extremely effective against many types of microorganisms including bacteria, fungi and viruses. For instance, the product label for Purex household bleach claims it is effective against Staphylococcus and Streptococcus bacteria, Influenza A and B viruses and athletes foot fungus. However, the label also says a surface must be pre-cleaned before using the chlorine bleach solution.
There are disadvantages of using chlorine bleach as a disinfectant. Many institutions do not commonly use chlorine bleach products because of the following: 1. lacks detergency—they contain no wetting agents to allow the disinfecting agent to penetrate soils, so surfaces must be pre-cleaned before the chlorine bleach will effectively kill germs; 2. very caustic to human tissues—can burn skin and eyes; 3. reacts with other chemicals to create toxic byproducts and gases—incompatible with products that contain ammonia, hydrochloric acid, phosphoric acid and acetic acid (vinegar); 4. fumes can be irritating—occupants of buildings frequently complain about bleach and bleach-related odors migrating into their work areas; 5. can emit a carcinogenic gas if it comes in contact with formaldehyde, or is hyper-chlorinated by hot water; 6. extremely corrosive to metals—Chlorine bleach can attack and corrode metal surfaces as well as permanently discolor countertops; 7. discolor fibers and colored surfaces—carpets, entrance matting and clothing are just a few of the fibers that can be damaged when contacted by chlorine bleach solutions; 8. damage floor finishes—Chlorine bleach can attack the floor finish coatings on the floor requiring them to be removed and replaced; 9. rapidly inactivated by organic debris (blood, tissue, saliva, microbes); 10. diluted solutions quickly lose their effectiveness. Chlorine bleach is unstable and can lose its oxidizing and disinfecting strength rapidly compared to “quat” based disinfectant-cleaners and/or sanitizers.
Phenolics Based Solutions
Phenols or phenolic disinfectant-cleaners are not as corrosive as chlorine bleach. But they are aggressive enough to attack and damage floor finishes and sensitive flooring. Phenolic disinfectants are still the preferred product in a few health care facilities. They are used in areas where gross contamination of blood and body fluids subsist. Phenolics are effective against pathogenic bacteria like tubercle bacillus that cause tuberculosis. There are disadvantages of phenolic disinfectants and many institutions do not commonly use phenolic products because of the following: 1. can be toxic to skin and eyes (depigmentation can occur with long periods of exposure or use); 2. commonly causes sinus and respiratory tract irritation or problems; 3. corrosive to certain rubber and plastic surfaces; 4. Flammable; 5. can leave a film on a cleaned surface, creating a buildup that will eventually need removal; 6. solutions need to be discarded and remixed daily; and 7. Expensive.
Quaternary Ammonium Chlorides
Quarternary ammonium chlorides or “quats” as they are commonly known are based upon the active ingredient benzalkonium chloride. These quaternary salt compounds can be formulated with a variety of ingredients to provide a safe and effective neutral pH, disinfectant-cleaner without damaging floor finishes or sensitive floor surfaces. Quats are effective in destroying a broad spectrum of harmful microorganisms. They are effective in killing many pathogenic microorganisms while cleaning the surfaces upon which they reside—all in one simple step. There are disadvantages of quaternary ammonium chlorides as follows: 1. quaternary ammonium chlorides do not kill tuberculosis; 2. do not perform especially well when challenged by organic soil. Quaternary ammonium chlorides do not provide residual activity on hard surfaces. The biggest single problem with the use of quaternary ammonium chlorides is their inconsistent efficacy against moulds, particularly Aspergillus; 3. quaternary ammonium chlorides have also had trouble with ever-present microorganisms such as E. coli and Pseudomonas; 4. quaternary ammonium chlorides have been suspected in developing microorganism's resistance to QAC quaternary ammonium chlorides after long periods of reappeared use.
Alcohols (Such as Ethyl and Isopropyl Alcohol, for Example)
Ethanol and Isopropyl alcohol are both excellent disinfectants whose germicidal properties are generally underestimated. Both are rapidly bactericidal against vegetative bacterial forms, tuberculocidal, fungicidal, and virucidal. The disinfectant properties of both ethanol and isopropyl alcohol rapidly drop at concentrations below fifty percent (50%) and above ninety percent (90%). The recommended concentration for use is sixty-ninety percent (60-90%) by volume. There are disadvantages of alcohols, as follows: 1. both ethanol and isopropyl alcohol are volatile and flammable compounds and must only be used with adequate ventilation; 2. alcohols, in general, are destructive to rubber compounds and to most of the cement and glues used in instruments, especially optics.
Thus, there is a considerable need for better and improved antimicrobial compositions.